Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations present, the description carries the transparency burden. It discloses the return format (price per unit in SUN) and implies a read-only operation by using 'Get'. However, it omits details about potential response size, authentication requirements, or real-time vs. delayed data, leaving some behavioral aspects unstated.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.